async def _make_pings_task(self):
""" Task that sends pings to all subscriptions in the queue.
All subs in this queue have timed out.
"""
while True:
await self._check_timeouts()
while not self._ping_pong_tasks.empty():
try:
subscriber = await self._ping_pong_tasks.get()
if subscriber.is_dead():
self._delete_subscription(subscriber)
else:
await subscriber.ping()
except (ConnectionResetError, BrokenPipeError):
Log.err(f'Connection unexpectedly closed {subscriber}')
self._delete_subscription(subscriber)
finally:
# We want to remove the task from the queue regardless
# if it fails or completes.
self._ping_pong_tasks.task_done()
# Go idle so other tasks can run.
await asyncio.sleep(TASK_DELAY_PING)
async def _enter_ping_pong(self) -> None:
self._alive = True
while self._alive:
packet = await self.read()
if packet.cmd == protocol.Commands.NEW_DATA:
# New data published!
await self._ack_new_data()
# Unpack the data and send it to callback.
data = packet.data.decode('utf-8')
if self._data_received is not None:
self._data_received(data)
else:
Log.err(f'No callback for new data provided!\n{data}')
else:
# Expecting a ping
if not await protocol.async_cmd_ok(packet,
protocol.Commands.PING):
Log.err('Failed to get ping command. Exiting.')
return
# Send a PONG back.
await self._pong()
Log.debug('[Client] Pong')
# If provided, call pong callback.
if self._pong_callback is not None:
self._pong_callback()
await asyncio.sleep(SLEEP_DELAY)
async def start(self, topic: str) -> bool:
"""
Starts the subscription.
param data_received is a callback that will be called
when new data arrvies at the subscribed topic.
"""
# Start connection and initialize a new Subscription.
await self.open()
await self.send(protocol.Commands.SUBSCRIBE)
# Wait for ACK, before sending the topic.
packet = await self.read()
if not await protocol.async_cmd_ok(
packet, protocol.Commands.SUBSCRIBE_ACK, self._writer):
return
# Send the topic we want to subscribe to.
await self.send(protocol.Commands.SUBSCRIBE,
data=topic.encode('utf-8'))
# Wait for OK/NOT OK.
sub_ack = await self.read()
if not await protocol.async_cmd_ok(sub_ack,
protocol.Commands.SUBSCRIBE_OK):
Log.err(f'Failed to subscribe to {topic}. Got no ACK.')
return False
# Enter ping-pong state where we just wait for data published to
# the chosen topic and give the data to the callback function provided.
await self._enter_ping_pong()
def _set_identifier(self, topic: str) -> None:
""" Sets the identification of the subscription.
This consists of:
1. Topic
2. File descripter number from reader/writer stream.
"""
self.topic = topic
try:
self.fd = self._writer.get_extra_info('socket').fileno()
except AttributeError:
# Streams are incorrect
Log.err(f'Incorrect streams to subscription to {self.topic}')
self.fd = None
async def ping(self) -> None:
""" Pings the subscriber and waits for a PONG back.
If the subscriber doesn't pong back, the subscription is closed.
"""
await protocol.send_packet(self._writer, protocol.Commands.PING)
Log.debug(f'Ping {self}')
pong = await protocol.read_packet(self._reader)
if await protocol.async_cmd_ok(pong, protocol.Commands.PONG):
# If PONG, reset timer.
self._time = 0
else:
Log.err(f'Bad ping! {self._alive} -> {self._state}')
# If no PONG, advance to next state, and potentially close.
alive = self._next_state()
if not alive:
self.die()
async def publish(self, topic: str, message: str) -> bool:
"""
Returns if the publish is succesful or not.
Throws ConnectionRefusedError.
"""
publish = AsyncPublish(self._ip, self._port)
try:
pub_ok = await publish.start(topic, message)
except ConnectionRefusedError:
Log.err(f'[Client ]Failed to connect to server {self._ip} '
f'on port {self._port}')
return
if pub_ok:
Log.info(f'[Client] Published "{message}" to topic "{topic}"')
else:
Log.info(f'[Client] Failed to publish "{message}" to'
f' topic "{topic}"')
return pub_ok
def get() -> dict:
"""
Returns the configurations.
If can't find the configuration file, default parameters are used
and a new one is created on disk.
"""
success = False
# Only need to read the config once (assumes no live-changes).
if Config._config is None:
try:
with open(CONFIG_PATH, 'rb') as f:
Config._config = json.load(f)
success = True
except FileNotFoundError:
Log.err(f'Failed to find config at {CONFIG_PATH}')
except json.decoder.JSONDecodeError as e:
Log.err(f'Failed to parse JSON {e}')
if not success:
Config._config = Config.__default
Config._save_config(Config._config)
return Config._config
